A research team led by Macquarie University Professor Mark Taylor has identified the high levels of lead around the northwestern Queensland town of Mount Isa as coming “unequivocally” from local mining operations.

For years, successive state governments, the Mount Isa town council and the Xstrata mining company insisted that the dangerous lead levels were the result of the natural environment and geology but this latest study demonstrates that mining activity is directly responsible for the health risks to residents, especially children.

The study, published in the peer-reviewed journal Environmental Pollution, has come after eight years of testing in the town. The researchers looked for levels and samples of lead in local waterways, soils, geology and households. They discovered that the lead isotopic signatures or “fingerprints” found in the town matched those from Xstrata’s nearby smelter, demonstrating that the lead did not come from natural sources.

Children, because they are still growing, are especially vulnerable to the harmful effects of lead. Unborn fetuses are at acute risk, as lead is deposited into their bodies from their mothers. Learning difficulties, decreased bone and muscle growth and damage to the nervous system are the result.

In 2008 a study by Queensland Health of 400 children from Mount Isa found that 11 percent had blood levels higher than the international safe level. One child was discovered to have three times the safe limit.

Mount Isa, founded as a mining settlement in the 1920s, has mostly produced lead, silver, zinc and copper. A smelter chimney, built in 1978, dominates the town. In 2003, Swiss-based Xstrata, one of the world’s largest mining corporations, purchased Mount Isa Mines for $A4.93 billion. The town depends heavily on the mining operation, which directly employs about 20 percent of its inhabitants.

Compelling new evidence shows Mount Isa mine emissions are contaminating the city and are the cause of childhood lead poisoning: here.